Re: [Starlink] Starlink Digest, Vol 12, Issue 6

[Ulrich Speidel <u.speidel@auckland.ac.nz>]

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On 5/03/2022 7:38 pm, Dick Roy wrote:
>
> -----Original Message-----
> From: Starlink [mailto:starlink-bounces@lists.bufferbloat.net] On 
> Behalf Of Ulrich Speidel
> Sent: Friday, March 4, 2022 4:14 PM
> To: David Lang
> Cc: starlink@lists.bufferbloat.net
> Subject: Re: [Starlink] Starlink Digest, Vol 12, Issue 6
>
> True, but Starlink is designed as a high bandwidth, low latency (OK, we
>
> won't mention their bufferbloat issues again here), and (currently) low
>
> user density service.
>
> Bandwidth-wise, good old Shannon and Hartley are agnostic about whether
>
> you divide your channel between 1 or a million users.
>
> */[RR] But they are assuming a “single” channel in the time domain.  
> When you can take advantage of other dimensions (eg. space) to create 
> more channels, (aka SDMA) the capacity goes up!/*
>
/*Taken as read - but it's beside the point. Shannon-Hartley allows you 
to do what was proposed - turning a channel that supplies a small number 
of users with a lot of capacity each into one that supplies a large 
number of users with a little capacity each, and of course if you add 
diversity (space, polarisation, ...) then this applies even more so. But 
the point is that each communication system is designed around an 
expectation of how many users will access it, and that you can't simply 
take an existing technology and somehow assume that it will work with a 
larger number of users just because it's theoretically possible. 
Basically, you can't simply throw more dishys at the problem if you need 
to serve more users.*/

-- 
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Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)

The University of Auckland
u.speidel@auckland.ac.nz  
http://www.cs.auckland.ac.nz/~ulrich/
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